Shaft locking device



Nov. 4, 1969 H. T. SIMMONS ET AL 3,476,892

I v V SHAFT LOCKING IJEVICE Filqd Deg. 14, 196? 2 Sheets-Sheet 1 4 72 INVENTORS b man 2m F145 2 Now 4, 1969 H. T. SlMMONS ET 3,476;gz

SHAFT LOCKING DEVICE Filed Dec. 14, 1967 2 Sheets-Sheet 2 INVENTORS HAROLD T. SIMMONS RICHARD E. PERVORSE ATTORNEY Un ted Sta Patmt ABSTRACT OF THE DISCLOSURE Shaft locking means carried by a cam carrying shaft prevents the manual rotation of a constant speed timing mechanism during the time interval the unit is in operation. Indexing the cam carrying shaft in one direction starts the timer and initiates cooperation between the shaft and the shaft locking means so as to lock the shaft thereby preventing rotation except by the timer motor. Indexing of the cam carrying shaft in another direction termi: nates cooperation between the shaft locking means and the shaft thereby releasing the shaft for manual rotation in a predetermined direction. I

This invention applies to a novel shaft locking device for use as a constant speed timing mechanism such as used in appliances such as automatic dryers, washers and the like.

Several of the presently available timing mechanisms employ a cam assembly means including at least one programming cam which is rotated byv a motor in onedirection to actuate the proper combination of circuitsat pre determined times.. As applied to a washing machine, such.-

circuits control the washing, extracting, rinsing, drying and the like of the machine. Frequently, the operator de sires to alter the prescribed program, and therefore the timing mechanism includes a manual knob connected to the main timer cam through a camcarrying shaft for advancing the main timer cam to the desired portion of the program. If, however, alteration of the program is done while the appliance is in operation, the variousv components of the appliance are advanced quickly through their various cycles thus subjecting-thecooperatively associated relays, solenoids, electrical contacts and the like to p08- sible-damage.

. The. present invention contemplates the utilization of improved structure which prevents the manual advance of a cam carrying shaft of a constant speed unit during the time that the appliance is in operation. To this end, in accordance with the principles of this invention, a shaft locking device is provided that is particularly useful for timing mechanisms of the type which employ an axially displaceable cam carrying shaft, the .axial displacement of which determines the state of actuation of the master switch of the timing mechanism.

According'ly, it is an object of the present invention to provide a shaft locking device which prevents the manual rotation of a cam carrying shaft during the time a timing mechanism is in operation.

Another object of the invention is to provide such a device for a timing mechanism of the type which employs an axially displaceable cam carrying shaft, the axial displacement of which opens and closes a master switch in the mechanism.

Still another object of the invention is to provide such a device that is directly connected to the cam carrying shaft of a timer mechanism. 7

Another object of the present invention is to provide such a device wherein indexing of the cam carrying shaft in one direction to initiate programming of an appliance locks the shaft from rotation except from rotation by the driving means of the timing mechanism.

Patented Nov. 4,, 1969 Yet another object of the invention is to provide such a device whereby the indexing of the cam carrying shaft in one direction releases the shaft for manual rotation. Another object of the invention is to provide such a device whereby the manual rotation of the shaft is limited to a. predetermined direction.

Another object of the invention is the provision of such a device wherein engagement of the ratchet means with drive means of the timing mechanism prevents manual rotation of the cam carrying shaft through the resistance of the drive means.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in a novel shaft locking device for a'constant speed timing mechanism substantially as described herein and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the. invention here disclosed may be made as come within the scope of the claims.

In the drawings: FIGURE 1 is a side elevation of a timing mechanism with a portion of the timing mechanism being removed to show the shaft locking device of the present invention. FIGURE 2 is a View similar to that of FIGURE 1 showing the timing mechanism in a different operating mode from that of FIGURE 1.

FIGURE 3 is an exploded view of the novel shaft locking device of the timing mechanism showing its relationship to various other components of the mechanism.

FIGURE 4 is an enlarged view of the ratchet means of the shaft locking device showing the relationship of its component parts in one mode of operation.

advanced to the desired starting point with the cycle under a no load condition. The novel shaft locking device includes ratchet means carried by the cam carrying shaft, such ratchet means including a ratchet non-advance means, ratchet-drive gear means, ratchet drive gear stop means,

' a ratchet non-back-up means, and a clutch spring surrounding the cam carrying shaft and being disposed between the cams and the ratchet means. The ratchet drive gear stop means limits the axial displacement of the ratchet drive gear means when the cam carrying shaft is axially displaced in. a, predetermined direction. The ratchet drive gear means engages a driving meansfor the timing mechanism such that manual rotation of the cam carrying shaft in either direction is prevented because of the resistance of the driving means. a

Referring now to FIGURES l-3 there is shown a timing mechanism 10 having a plurality of rotatable cams 12 carried on a shaft 14, the shaft being rotatably journalled in the spaced apart end plates 16 and 18. The cam carrying shaft projects through an aperture in the end Plate 16 and is retained by journal means 11 attached or otherwise formed on the end plate 18. Included'as part of the timing mechanism are spaced apart terminal plates 20 and 22 respectively, each of which carries a plurality of stationary electrical terminals 26 and movable electrical terminals 24, the movable terminals being hinged to their respective plate. The terminals are so arranged on each plate such that when the unit is assembled, a movable terminal interfits between a corresponding stationary terminal. The electrical contacts 24a of the movable terminals engage the eectrical contacts 26a of the stationary the rise and fall peripheral contours 25 of thecams 12.

Also included as part of the timing mechanism is a master switch means 28 including an electrical terminal 30 which is electrically connected to a fixed electrical 'contact32 and movable contact blade 36. Contact 34, carried by. the movable contact blade, is adapted to engage with fixed contact 32. Blade 36 is hinged to a plate 16 such that upon engagement of the free end of the blade 36 with the cam 12a upon axial displacement of the shaft 14, contact :34 is displaced so as ,to engage with contact 32 thereby connecting a power source (not shown) to the motor of the timing mechanism. Cam carrying shaft 14 moves axially within the timing mechanism and is indexed to either one of two positions. -As shown in FIGURE 1, the shaft has been indexed outwardly from the timing mechanism such that cam 12a engages blade 36 so as to engage the fixed and movable contacts of the master switch. In FIGURE 2, the cam carrying shaft is shown indexed so as to disengage cam 12a from blade 36 to thereby, disengage contacts 32 and 34. The shaft is secured in each of these positions by a substantially U-shapedretaining means 38 having fingers 38a and 38b adapted to engage the detents 40 and 41 formed in the cam carrying shaft.

As is illustrated in FIGURE 3, the timing mechanism is operated by a driving means, here illustrated as a synchronous motor 42 and gear train 44, the cam carrying shaft 14 of the timer mechanism being activated by the motor through the gear train. Gear train 44 includes reduction gears 46 and 48. The cam carrying shaft 14 is connected to the gear train through ratchet drive gear 50 and pinion 52. As will be described hereinafter, ratchetdrive gear 50 is part of the novel shaft locking device.

In general, the shaft locking device comprises a ratchet means 54 including a ratchet non-advance means 56, which prevents manual rotation of the shaft, ratchet drive gear 50, ratchet non-back-up means 58 which limits the direction of manual rotation of the shaft, and clutch spring means 60. Clutch spring means 60 is separated from cam 12b by washer 62. Ratchet drive gear 50 includes gear teeth 53 adapted to engage the teeth of pinion 52. Also included in ratchet drive gear 50 are two sets of ratchet teeth 51 formed on opposite faces of the gear. Such ratchet teeth are adapted to engage the ratchet teeth 55 of ratchet non-advance means 56 and ratchet teeth 57 of ratchet non-back-up means 58.

Ratchet non-advance means 56 has a hub 66 extending from the face thereof. Hub 66 contains a double-D shaped aperture 64. The aperture 64 mates a corresponding dou ble-D portion of the shaft 14 such that the ratchet non-advance means 56 can be fixedly held to the cam carrying shaft through knurl 17. Ratchet drive gear 50 and ratchet non-back-up means 58 float on the shaft 14. Axial alignment between the mating ratchet teeth of the ratchet non-advance means 56, ratchet drive gear 50, and ratchet non-back-up means 58 is insured through cars 68 which are adapted to engage slots 70 formed in hub 66. Hub 66 extends through ratchet drive gear 50 through aperture 50a. Ratchet 'drive gear and ratchet non-back-u'p means 58 are spring biased against the ratchet non-advance means 56 through spring clutch 60 having'lanced ears 74. The spring insures that the teeth of the ratchet means are properly engaged.

The operation of the timing mechanism and the novel shaft locking device can'now be described withparticular reference to FIGURES 1, 2, 4 and 5. As shown'in FIGURE 1, shaft 14 has been indexed so that the master switch 28 has been closed for timer operation;'that is, timer motor 42 is energized. The shaft is locked in the outward position byenga'gement of retaining means 38 with detent 40 of the shaft. With the shaft so indexed, ratchet non-advance means 56 and ratchet non-back-up means 58 will both be engaged with ratchet drive gear 50 as is shown in FIGURE 5. With the ratchet means so engaged, manual rotation of cam carrying shaft 14 is prevented because of the resistance of the driving means;

that is, the friction developed through the motor and the gear train. Cam carrying shaft 14 will be rotated in the direction of the motor rotation; that is, in a clockwise direction. The shaft is rotated through pinion 52 which is engaged with gear 53 of ratchet drive gear 50, the ratchet drive gear being engaged with ratchet non-back-up means 58 and ratchet non-back-up means 58 being engaged With the ratchet non-advance means 56 through the engagement of the ears 68 with slots 70 of hub 66. Since ratchet non-advance means 56 is fixedly held to'the shaft 14, shaft 14 .will rotate in accordance with the output of the motor of the timing mechanism.

When shaft 14 is indexed as shown in FIGURE 2, and with retaining means 38 being engaged in detent 41, master switch 28 will be open. As the shaft 14 is axially indexed inwardly, ratchet drive gear 50 biases against ratchet drive gear stop means 50b. Ratchet drive gear stop means consists of a plurality of tang means 72, the tang means being lanced from support plate 18. Such biasing of the. ratchet drive gear 50 allows ratchet nonadvance means56 to be disengaged from the ratchet drive gear 50. This is more clearly shown in FIGURE 4. With the-ratchet drive gear being thus disengaged, shaft 14 can be manually rotated. Since ratchet non-back-up means 58 is connected-t0 the ratchet non-advance means 56 through ears 68 being engaged with slots 70, ratchet nonback-up means 58 will rotate in accordance with the rotation of cam carrying shaft 14 and the ratchet nonadvance 56. As shown in FIGURE 4, the ratchet teeth of the ratchet non-back-up means 58 and the teeth of ratchet drive gear are both pointed in the same direction. Therefore, the ratchet non-back-up means 58 will be free to rotate independent of the ratchet drive gear 50 so long as the shaft 14 is turned, as is indicated by the arrow, in a clockwise direction. Conversely, manual rotation of the shaft 14 in a counterclockwise direction will be prevented since the teeth of the ratchet non-back-up means 58'and the ratchet drive gear 50 will not be able to become disengaged. Such limitation of a clockwise rotation is highly desirable since it prevents the rise and fall peripheral contours 25 of the cams 12 from being engaged with the movable terminals 24 in the wrong direction. While the device has been described as being limited to a clockwise manual rotation, it should be understood that the invention need not be so limited. Reversing the teeth direction from that shown would limit the manual rotation to a counterclockwise direction.

Thus there is described a novel shaft locking device for constant speed. timing mechanisms having an axially displ'aceable, cam carrying shaft and wherein displacement of the cam carrying shaft opens and closes the timer master switch. The shaft locking device prevents manual rotation of the cam carrying shaft in either direction when the timing mechanism is in operation. A simple indexing of the shaft, in addition to opening the master switch, permits the shaft to be manually rotated in a clockwise or otherwise predetermined direction when the timing mechanism is not in operation. And, as noted above,-- the manual rotation is limited to such predetermineddirection such that rotation of the shaft will not cause therise and fall contours of the cams carried by the shaft tobecome improperly engaged with the movable terminals of the timer. Thus, from the foregoing description, taken in conjunction with the accompanying figures of the drawing, it will be readily apparent to those skilled in the art that this invention provides a new and improved shaft locking device for a constant speed timer, the features of which may be applied to various arts and devices.

"-'-What is claimed is:

1. A shaft locking device for an axially displaceable,

rotatable, motor driven shaft comprising a ratchet noncarried by said shaft, both the ratchet drive gear and the ratchet non-back-up means being spring biased against said ratchet non-advance means, said ratchet drive gear having means to engage a gear train of a motor driving said shaft and stop means to limit the axial displacement of said ratchet drive gear when said shaft is axially displacement of said ratchet drive gear when said shaft is axially displaced in a predetermined direction.

2. A shaft locking device for an axially displaceable, rotatable, motor driven shaft comprising a ratchet nonadvance means fixedly carried by said shaft, a ratchet drive gear and a ratchet non-back-up means floatably carried by said shaft, both the ratchet drive gear and the ratchet non-back-up means being spring biased against said ratchet non-advance means, said ratchet non-advance means having ratchet teeth adapted to engage a first set of ratchet teeth of said ratchet drive gear and having a hub with a plurality of slots formed therein, said hub extending through said ratchet drive gear such that a plurality of ears formed in said ratchet non-back-up means engages said slots, said ratchet non-back-up means having teeth adapted to engage a second set of ratchet teeth of said ratchet drive gear, said ratchet drive gear having means to engage a gear train of a motor driving said shaft and stop means to limit the axial displacement of said ratchet drive gear when said shaft is axially displaced in a predetermined direction.

3. A constant speed motor driven timing mechanism comprising an axially displaceable cam carrying shaft rotatably journalled in a pair of end plates, a plurality of cams fixedly mounted on said shaft and having means to close a plurality of electrical contacts according to a program-med sequence as said shaft is rotated, a master switch adapted to be opened and closed in accordance with the axial displacement of said shaft, a shaft lock means comprising a ratchet non-advance means fixedly carried by said shaft, a ratchet drive gear and a ratchet non-back-up means fioatably carried by said shaft, both the ratchet drive gear and the ratchet non-back-up means being spring biased against said ratchet non-advance means, said ratchet non-advance means having ratchet teeth adapted to engage a first set of ratchet teeth of said ratchet drive gear and having a hub with a plurality of slots formed therein, said hub extending through said ratchet drive gear such that a plurality of ears formed in said ratchet non-back-up means engages said slots, said ratchet non-back-up means having teeth engaging a second set of ratchet teeth of said ratchet drive gear, said ratchet gear having means to engage a gear train of a motor driving said shaft and stop means to limit the axial displacement of said ratchet drive gear when said shaft is axially displaced in a predetermined direction.

4. In a timing mechanism having an indexable cam carrying shaft; a shaft locking means comprising: a ratchet means carried by said cam carrying shaft, said ratchet means including means coupling said ratchet means to a drive means of said timing mechanism, means engaging said coupling means preventing manual rotation of said cam carrying shaft, means limiting the direction of manual rotation of said cam carrying shaft when said cam carrying shaft is axially displaced to disengage said means preventing manual rotation of said cam carrying shaft from said coupling means; and means limiting the axial displacement of said coupling means when said cam carrying shaft is axially displaced.

5. In a timing mechanism according to claim 4, Wherein said means coupling said ratchet means to a drive means of said timing mechanism is a gear means.

6. In a timing mechanism according to claim 5, wherein said means preventing manual rotation of said cam carrying shaft includes ratchet teeth engaging teeth disposed on a face of said gear means.

7. In a timing mechanism according to claim 5, where in said means limiting the direction of manual rotation of said cam carrying shaft includes ratchet teeth engaging teeth disposed on a face of said gear means.

8. In a timing mechanism according to claim 5, wherein said gear means and said means limiting the direction of manual rotation of said c-am carrying shaft float on said cam carrying shaft and are spring biased against said means preventing manual rotation of said cam carrying shaft.

9. In a timing mechanism according to claim 5, wherein said drive means includes a motor and a gear train coupled to said gear means.

10. In a timing mechanism according to claim 4, wherein said means limiting the axial displacement of said coupling means includes tabs lanced from the housing of said timing mechanism.

11. In a timing mechanism according to claim 4, wherein there is further included a means to position said cam carrying shaft when it is axially displaced.

12. In a timing mechanism according to claim 11, wherein said positioning means includes a retaining means carried by the housing of said timing mechanism and detent means carried by said cam carrying shaft, said retaining means engaging said detent means.

References Cited UNITED STATES PATENTS 3,371,170 2/1968 Thomas et al. 20038 MILTON KAUFMAN, Primary Examiner US. Cl. X.R. 74-3.5; 192-12 

